Membrane-Coupled Ultrasonic Probe System for Detecting Flaws in a Tubular

ABSTRACT

An ultrasonic probe apparatus for detecting flaws in a tubular includes a probe housing. The probe housing has an axial axis, a central cavity lying along the axial axis, and a bottom face adapted for placement on the tubular. The bottom face of the probe housing has an opening in the middle. A probe support is disposed within the central cavity and rotatable about the axial axis of the probe housing. An ultrasonic probe is mounted on the probe support and has a scanning face exposed to the opening of the bottom face of the probe housing, and may be coupled to the pipe with a liquid acoustic couplent medium.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from, and is a continuation-in-part ofpresently pending U.S. patent application Ser. No. 12/568,737, filed on29 Sep. 2009, which is incorporated by reference herein for all itcontains.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present disclosure relates generally to an ultrasonic probeapparatus, an ultrasonic probe system, and an ultrasonic probe methodfor detecting the presence of structural and material flaws in atubular. In particular, the disclosure relates to an ultrasonic probeapparatus which employs a single, handheld scanner and a singleultrasonic phased array probe to detect structural and material flaws,i.e. wall reduction, cracks or manufacturing defects, etc., which mayoccur to a tubular being manufactured or after being in operation. Inparticular, the probe apparatus is designed and operated in a manner tospecifically determine the thickness of a wall and unacceptable defectsin a pipe.

2. Description of the Related Art

Non-destructive ultrasonic test methods are commonly used in theinspection of tubulars for structural and material flaws, e.g., cracksin the tubular walls, unevenness in the thickness of the tubular walls,and delaminations and inclusions in the tubular walls. Single-elementand multi-element ultrasonic probes have been used in the tests. Theprobes are physically oriented in different directions to detect flawswith different orientations, such as longitudinally-oriented flaws,transversely-oriented flaws, and obliquely-oriented flaws. Detection inmultiple orientations using a single ultrasonic probe requiresmechanical adjustment of the tilt angle of the probe for each differentorientation, which is costly and time-consuming. Recently, ultrasonicphased array technology was introduced allowing flaw detection inmultiple orientations. Since the ultrasonic beams from a phased arrayprobe can be steered/tilted electronically rather than mechanically,this enables one using the phased array technology to detect flaws withvarious orientations in a much more efficient way. Moreover, in view ofthe fact that the multiple elements in a phased array are divided intodifferent groups that can be activated in sequence to inspect differentlocations on the test piece, a phased array probe is capable of scanninga large inspection area without movement.

European Patent Publication No. EP 1918700 A1 discloses a method fordetecting flaws in tubulars using a phased array probe. The methodincludes arranging the phased array probe to face a tubular test object.Selected transducers in the probe transmit and receive ultrasonic wavessuch that ultrasonic waves are transmitted in the tubular in a pluralityof different propagation directions. Transmission and reception timeshifts are used to control transmission and reception of ultrasonicwaves by the probe. The ultrasonic testing condition is such that therespective external refraction angles (or internal refraction angles) ofthe ultrasonic wave in the plurality of propagation directions areapproximately equivalent. The transducers are arranged in a matrix alongan annular curved surface designed such that the aforementionedultrasonic testing condition can be achieved.

In European Patent Publication No. EP 1918700 A1, the phased array isconfigured as a two-dimensional array, which is expensive and complex tocontrol. At present, one-dimentional dimensional (1D) phased array isbeing mostly used for industrial applications. For a one dimensionalphased array, despite the presence of the electronic steering, it isstill necessary to partly perform physical tilting of the probe in orderto detect flaws in all orientations. Certainly, being able to quicklyand easily tilt the probe is crucial in practice and is addressed inthis disclosure.

BRIEF SUMMARY OF THE INVENTION

Ultrasonic nondestructive testing (NDT) methods are commonly used in theinspection of oil country tubular goods. Both manual inspection systemsand automated inspection systems have been used for many years.Conventionally, one or more single element ultrasonic probes ormulti-element array probes have been used in these systems, and arephysically oriented in different directions to detect flaws withdifferent orientations, such as longitudinally oriented flaws,transversely oriented flaws, and obliquely oriented flaws. A given probecan only detect flaws in its specified orientation. Ultrasonic phasedarray technology has been introduced into the field in recent years.Ultrasonic beams from a phased array probe can be electronically steeredto a direction in the azimuth (scanning) plane other than the axialdirection of the probe. A single phased array probe still can not detectflaws in all orientations in current inspection systems.

Thus, according to a first aspect of the present invention, anultrasonic phased array probe apparatus for detecting flaws in a tubularcomprises: a probe housing having an axis, a central cavity lying alongthe axial axis, and a bottom face adapted for placement on the tubular,the bottom face having an opening in the middle; a probe supportdisposed within the central cavity of the probe housing and rotatablethe axial axis of the probe housing which allows the thickness of thewall of the pipe to be measured and flaws to be detected.

In another embodiment, an ultrasonic probe is mounted on the probesupport and has a scanning face exposed to the opening of the bottomface of the probe housing, the scanning face being oriented relative toa selected plane of the tubular by rotation of the probe support aboutthe axial axis of the probe housing. In at least certain embodimentsdisclosed herein, are systems and methods which employ a single handheldscanner and a single ultrasonic phased array probe to detect wallreduction and longitudinally oriented, transversely oriented, andobliquely oriented flaws in pipes. The phased array probe is mounted onthe handheld scanner and the azimuth (scanning) plane of the probe isparallel to the axis of the pipe. The scanner is designed such that theprobe can be tilted in the radial plane of the pipe. When the probe istilted into vertical position, ultrasonic beams can be generated todetect wall reduction if all the active array elements have equal orsymmetrical time delay values, or ultrasonic beams can be generated todetect transversely oriented flaws if the elements have unequal timedelay values. When the probe is tilted into non vertical positions,ultrasonic beams can be generated to detect either longitudinallyoriented flaws if all the active array elements have equal orsymmetrical time delay values, or obliquely oriented flaws if theelements have unequal time delay values. The systems and methodsdisclosed in the present invention can detect obliquely oriented flawsthat are in any angle with the axis of the pipe.

In another embodiment, the ultrasonic phased array probe apparatus fordetecting flaws in a tubular comprises: a probe housing having a cavityadapted to contain a liquid acoustic couplant and a phased array probemounted in a back wall of the cavity in the housing; a flexible andconformable acoustic coupling membrane mounted to the probe housing andadapted to contact the tubular and the membrane protrudes from the probehousing to acoustically couple with the tubular and transmit theultrasound between the phased array probe and the tubular; a fluidregulating device installed to the probe housing allowing the liquidacoustic couplant medium to be injected into and released from thecavity of the probe housing to control the fluid pressure in the cavity;and a beam angle position block conforming to the outside surface of thetubular, and orienting the phased array probe with the tubular.

The tilting of the probe is achived by a beam angle position block thatis attached to the bottom of the scanner housing and the beam angleposition block rides on the pipe outside surface. The beam angleposition block can be quickly and easily attached and detached from thehousing. Ultrasound from the phased array probe is coupled into the pipethrough direct contact between a membrane on the scanner and the pipeoutside surface.

In certain embodiments of the first aspect of the present invention, thebottom face of the probe housing is curved for placement on the tubular.

In certain embodiments of the first aspect of the present invention, theultrasonic probe is a phased array probe.

In certain embodiments of the first aspect of the present invention, theprobe support is provided with a fluid port for delivering fluid to aportion of the central cavity of the probe housing adjacent to thescanning face of the ultrasonic probe.

In certain embodiments of the first aspect of the present invention, thebottom face of the beam angle position block is curved for placement onthe tubular.

In certain embodiments of the first aspect of the present invention, thecavity between the phased array probe and the membrane is filled withliquid acoustic couplant.

In certain embodiments of the first aspect of the present invention, themembrane has an acoustic impedance substantially similar to the acousticimpedance of the liquid acoustic couplant medium and seals the acousticcouplant within the cavity, to allow an ultrasonic coupling between theultrasonic probe and a surface of the tubular.

In certain embodiments of the first aspect of the present invention, thebeam angle position block may be detached from the housing.

In another aspect of the present invention, an ultrasonic probe systemfor detecting flaws in a tubular comprises: a probe housing having anaxis, a central cavity lying along the axial axis, and a bottom faceadapted for placement on the tubular, the bottom face having an openingin the middle; a probe support disposed within the central cavity of theprobe housing and rotatable about the axial axis of the probe housing;an ultrasonic probe mounted on the probe support and having a faceexposed to the opening of the bottom face of the probe housing, thescanning face being oriented relative to a selected plane of the tubularto provide a measurement of the thickness of the wall of the pipe anddetect flaws in that location, the ultrasonic probe having probeelements configured to generate and receive ultrasonic beams; and aphased array controller for selectively applying varying time delays toprobe elements in the ultrasonic probe such that the ultrasonic beamsgenerated by the ultrasonic probe are steered into a direction in or offthe normal direction of the ultrasonic probe.

In certain embodiments of the second aspect of the invention, the bottomface of the probe housing is curved for placement on the tubular.

In certain embodiments of the second aspect of the present invention,the ultrasonic probe system further comprises a lock arrangement forselectively preventing rotation of the probe support about the axialaxis of the probe housing.

In certain embodiments of the second aspect of the present invention,the probe support is provided with a fluid port for delivering fluid toa portion of the central cavity of the probe housing adjacent to thescanning face of the ultrasonic probe.

In certain embodiments of the second aspect of the present invention,the ultrasonic probe system further comprises an actuator coupled to theprobe support for selectively rotating the probe support about the axialaxis of the probe housing.

In certain embodiments of the second aspect of the present invention,the ultrasonic probe system further comprises a system controller thatissues command signals to the actuator, the actuator being configured torotate the probe support in response to the command signals.

In certain embodiments of the second aspect of the present invention,the system controller and the phased array controller cooperate toachieve selective steering of the ultrasonic beams generated by theultrasonic probe and selective tilting of the scanning face of theultrasonic probe.

In a third aspect of the present invention, a method of testing atubular for flaws comprises: mounting an ultrasonic probe on a probesupport rotatably supported within a central cavity of a probe housing;placing the probe housing on the tubular, with a scanning face of theultrasonic probe exposed to the tubular through an opening in a bottomof the probe housing; generating and receiving ultrasonic beams usingthe ultrasonic probe; selectively tilting the scanning face of theultrasonic probe by rotating the probe support so that the ultrasonicbeams generated by the ultrasonic probe are at an angle with an axialplane of the tubular; selectively electronically steering the ultrasonicbeams generated by the ultrasonic probe so that the ultrasonic beamsgenerated by the ultrasonic probe are at another angle with a radialplane of the tubular; and processing and interpreting the ultrasonicbeams received by the ultrasonic probe to determine if there are flawsin the tubular.

Other aspects and advantages of the invention will be apparent from thefollowing description and the appended claims.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, described below, illustrate typicalembodiments of the invention and are not to be considered limiting ofthe scope of the invention, for the invention may admit to other equallyeffective embodiments. The figures are not necessarily to scale, andcertain features and certain views of the figures may be shownexaggerated in scale or in schematic in the interest of clarity andconciseness.

FIG. 1 is a perspective view of an ultrasonic testing system includingan ultrasonic probe apparatus sitting on a tubular.

FIG. 2 is a vertical cross-section of the ultrasonic testing system ofFIG. 1 along an axial plane of the system.

FIG. 3 is a bottom view of the ultrasonic probe apparatus of FIG. 2.

FIG. 4 is an end-view of the ultrasonic probe apparatus of FIG. 2showing a lock arrangement for a probe support of the ultrasonic probeapparatus.

FIG. 5 is a vertical cross-section of an end portion of the ultrasonicprobe apparatus of FIG. 2 showing an alternate lock arrangement for aprobe support of the ultrasonic probe apparatus.

FIG. 6 illustrates an alternate lock arrangement for a probe support ofthe ultrasonic probe apparatus of FIG. 2.

FIG. 7 is a diagram of a phased array probe.

FIG. 8 is a diagram of an array of probe elements for use in a phasedarray probe.

FIG. 9 shows axial and radial planes of a tubular, and ultrasonic beamdirections for detecting flaws in different orientations.

FIG. 10 shows ultrasonic beams in a tubular for detectinglongitudinally-oriented flaws.

FIG. 11 shows ultrasonic beams in a tubular for detectingtransversely-oriented flaws.

FIG. 12 illustrates an ultrasonic probe system including the ultrasonicprobe apparatus of FIG. 2.

FIG. 13 illustrates another embodiment of the ultrasonic probe system ofthe present invention, wherein the membrane has been disassembled toexpose cavity and the face of the phased array probe.

FIG. 14 is a partially assembled view of the ultrasonic probe system ofFIG. 13, wherein beam angle position block has been partially detachedto show the membrane assembled to the probe housing.

FIG. 15 illustrates one embodiment of the ultrasonic probe apparatus ofthe present invention as it would be used to measure wall thickness anddetermine if there are transversely oriented flaws in a pipe beingtested.

FIG. 16 illustrates another embodiment of the ultrasonic probe apparatusof the present invention as it would be used to determine if there hasbeen longitudinally and obliquely oriented flaws in a pipe being tested.

FIG. 17 is a view of a typical membrane used for an ultrasonic probeapparatus of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

The present invention will now be described in detail, with reference tothe accompanying drawings. In this detailed description, numerousspecific details may be set forth in order to provide a thoroughunderstanding of the invention. However, it will be apparent to oneskilled in the art when the invention may be practiced without some orall of these specific details. In other instances, well-known featuresand/or process steps may not be described in detail so as not tounnecessarily obscure the invention. In addition, similar referencenumerals may be used to identify common or similar elements.

The present invention relates to an ultrasonic testing system capable offlexibly orienting a one-dimensional (but not limited to aone-dimensional) phased array probe in order to detect flaws in anydesired direction, (i.e. transverse, longitudinal, or oblique) relativeto the axial axis of a tubular.

FIG. 1 shows an ultrasonic testing system including an ultrasonic probeapparatus 10 placed on a tubular 12 for the purpose of detectingstructural or material flaws in the tubular 12. Examples of structuraland material flaws that may be detected include, without limitation,cracks in the wall of the tubular 12, unevenness in thickness of thewall of the tubular 12, and delaminations and inclusions inside the wallof the tubular 12. The tubular 12 may be, for example, an oilfieldtubular, e.g., a drill pipe, or other type of industrial tubular. Thetubular 12 may be made of various kinds of materials, for example,metal, plastic, fiber glass, or glass. Typically, the tubular 12 isrigid or semi-rigid.

FIG. 2 is a vertical cross-section of the ultrasonic testing system ofFIG. 1. In FIG. 2, the probe apparatus 10 includes a probe housing 14placed on the tubular 12 such that the axial axis 11 of the probehousing 14 is parallel to the axial axis 15 of the tubular 12. The probehousing 14 has a central cavity 17, which lies along the axial axis 11of the probe housing 14. The probe housing 14 has a bottom face 16, topface 20, end faces 26, and side faces (not shown), which together definethe boundary of the central cavity 17. The bottom face 16 is adapted formatching the external surface 13 of the tubular 12, as shown in FIG. 2.“Adapted for matching” means, for example, that the face profile of thebottom face 16 is similar to that of the portion of the external surface13 of the tubular 12 which the bottom face 16 touches. For a tubular 12having an external surface 13 that is curved, the bottom face 16 wouldalso be curved (see 16 in FIG. 5).

Typically, the surface profile of the bottom face 16 is such that theprobe housing 14 can sit on the tubular 12 with little or no gap betweenthe bottom face 16 and the external surface 13 of the tubular 12. Anopening 30 is provided in the middle of the bottom face 16. An opening18 is provided on the top face 20. Openings 22 are provided on the endsurfaces 26. The openings 18, 22, and 30 are connected to the centralcavity 17 of the probe housing 14.

The probe apparatus 10 includes a probe support 32 inserted in thecentral cavity 17 of the probe housing 14, with portions disposed in theopenings 22 on the end faces 26 of the probe housing 14. The probesupport 32 is a rotatable assembly. As an example, the probe support 32may be composed of wheels 34, 35 disposed within the openings 22 and asupport bar 36. The wheels 34, 35 are rotatable about the axial axis 11of the probe housing 14. The wheels 34, 35 are rigidly connected by asupport bar 36 so that when the wheels 34, 35 rotate about the axialaxis 11 of the probe housing 14 the support bar 36 also rotates aboutthe axial axis 11. Or the probe support 32 can be a single piece madefrom a cylinder which can rotate about the axial axis 11. Forconvenience, it is assumed that the probe support 32 is made of wheels34, 35 and support bar 36, but this should not be construed as limitingthe design of the probe support 32 to one that includes wheels and asupport bar. Although not shown, rotary seals may be disposed in theopenings 22 to seal between the probe housing 14 and the wheels 34, 35.One reason for providing rotary seals may be to prevent fluid in thecentral cavity 17, when there is fluid in the central cavity 17, fromleaking out of the probe housing 14 through the openings 22. Soundcoupling fluid may be supplied into the central cavity 17, as will beexplained in more detail below.

The probe apparatus 10 includes an ultrasonic probe 62 for detectingstructural and material flaws in the tubular 12. As shown in FIG. 2, thesupport bar 36 provides a mounting surface 60 for the ultrasonic probe62. The mounting surface 60 includes a window 64 through which thescanning face 66 (see also FIG. 3) of the ultrasonic probe 62 is exposedto the central cavity 17 and then the opening 30 in the bottom face 16of the probe housing 14. With this arrangement, the scanning face 66 ofthe ultrasonic probe 62 faces the portion of the tubular 12 to beinvestigated for flaws. The support bar 36, through its rotation aboutthe axial axis 11 of the probe housing 14 as described above, allows thetilt angle of the scanning face 66 and therefore the azimuth plane ofthe ultrasonic probe 62 to be adjustable relative to the axial axis 15(or an axial plane passing through the axial axis 15) of the tubular 12.The azimuth plane of the ultrasonic probe 62 is the plane that isperpendicular to the scanning face 66 and crosses the center points ofall probe elements in the ultrasonic probe 62. The support bar 36includes a fluid port 68 for delivering fluid into the space 55 (aportion of the central cavity 17 between the support bar 36 and thebottom face 16 of the probe housing 14 or a portion of the centralcavity 17 adjacent to the scanning face 66 of the ultrasonic probe 62).During flaw detection, sound coupling fluid is supplied to the space 55to provide sound coupling between the ultrasonic probe 62 and thetubular 12. Typically, the sound coupling fluid is water, but otherfluids, such as oil, may also be used.

In one embodiment, the probe apparatus 10 may include a lock arrangementfor preventing rotation of the probe support 32 when the support bar 36is at a selected position corresponding to a selected tilt angle of thescanning face 66 of the ultrasonic probe 62. In one example, and withreference to FIG. 5, the lock arrangement includes radial holes 40formed at predetermined intervals on wheel 34 (of the probe support). Asmany holes 40 as desired, with any desired radial spacing between them,may be formed on the wheel 34. Typically, the radial span of the radialholes 40 would be determined by the desired range of tilt angles for theflaw detection. In the example of FIG. 5, the radial holes 40 are formedin the wheel 34 in diametrically-opposed pairs and are accessible fromthe exterior of the wheel 34. In the example of FIG. 5, the lockarrangement also includes diametrically-opposed holes 42 drilled in theprobe housing 14. The holes 42 extend from the exterior of the probehousing 14 to the opening 22 of the probe housing 14 where the wheel 34is mounted. To rotate the support bar (36 in FIG. 2) to a selected tiltangle, the wheel 34 is rotated such that a selected pair ofdiametrically-opposed radial holes 40 (corresponding to the selectedtilt angle) are aligned with the holes 42 in the probe housing 14. Then,locks 44, e.g., retractable plungers or screws, are inserted into thealigned holes 40, 42 to lock the wheel 34 to the probe housing 14.

Another example of a lock arrangement for preventing rotation of theprobe support (32 in FIG. 2) when the support bar (36 in FIG. 2) is at adesired position is shown in FIG. 4. In this example, radial marks 46are formed at predetermined radial positions on the face 37 of the wheel34 (of the probe support). A pointer mark 48 is formed on the end face26 of the probe housing 14 where the wheel 34 is mounted. Holes 50 arealso formed in the probe housing 14. The holes 50 are through-holes thatextend from the exterior of the probe housing 14 to the opening 22 ofthe probe housing 14 where the wheel 34 is mounted. To rotate thesupport bar (36 in FIG. 2) to a selected tilt angle, the wheel 34 isrotated such that a selected radial mark 46 (corresponding to theselected tilt angle) is aligned with the pointer mark 48. Then, locks52, e.g., retractable plungers or screws, are inserted in the holes 50to hold the wheel 34 at the selected position by pressure.

FIG. 6 shows another example of a lock arrangement for preventingrotation of the probe support 32 when the support bar 36 is at a desiredposition. In contrast to the previous examples, this lock arrangementmay be operated automatically. In the example of FIG. 6, an actuator 54is coupled to the wheel 34, e.g., via a shaft 55. The actuator 54 isoperable to incrementally rotate the shaft 55, and hence rotate thewheel 34 about the axial axis 11 of the probe housing 14. The actuator54 is equipped to hold the shaft 55 at a desired rotational position,which would also hold the wheel 34 fixed relative to the probe housing14 and maintain the support bar 36 at the desired tilt angle. Theactuator 54 may be, for example, a gear-type indexed shifter or otheractuator capable of imparting rotary motion to the wheel 34, on-demand,at desired rotational angle increments. For automatic operation, theactuator 54 may receive command signals from an external source androtate the probe support 32 (including support bar 36) according to thecommand signals, thereby allowing automatic shifting of the tilt angleof the ultrasonic probe 62 via rotation of the probe support 32 andsubsequent locking of the probe support 32 when the ultrasonic probe 62is at the desired tilt angle.

Returning to FIG. 2, the ultrasonic probe 62 may be a phased arrayprobe. “A phased array probe” is a multi-element ultrasonic transducerthat can be used to generate steered beams by means of phased pulsingand receiving. Phased array probes are available in the market. Oneexample of a phased array probe that may be used as the ultrasonic probe62 is Immersion Phased Array Probe-Flat, available from the GeneralElectric (GE) phased array probe catalog. FIG. 7 shows a typicalstructure of a phased array probe 62. The phased array probe 62 includesprobe elements 65, which are typically provided in multiples of eight,e.g., 16, 32, or 64, and are made of piezoelectric materials, such aspiezoelectric ceramic or piezoelectric composite. In FIG. 8, only a fewprobe elements 65 are shown to simplify the figure (the view in FIG. 8is from the top or bottom of the array). The probe elements 65 arecoupled by element wiring 67 to a multi-conductor coaxial cable 69. FIG.7 shows a one-dimensional arrangement of the probe elements 65. The dotsindicate that there can be as many probe elements 65 as deemedreasonable in the array. “A” represents the aperture of the probe, “P”represents the pitch or center-to-center distance of the probe, “W”represents the width of each probe element, and “H” represents theheight of each probe element. The smallest width of the probe element istypically 0.2 mm, and the largest width of the probe element istypically less than 1 mm. Narrower probe elements have more beamspreading, which influences the steering angle of the beam.

For illustration purposes, a phased array probe may have the followingparameters: W=0.3 mm, H=10 mm, P=0.8 mm, and 64 probe elements. However,this is just an example of a phased array configuration and in no wayimposes any limits on the ultrasonic probe 62, which may employ otherequally effective phased array configurations. It should be noted thatphased array configurations are not limited to the one-dimensionalarrangement shown in FIG. 8. Other arrangements may includetwo-dimensional square (where the probe elements are arranged as asquare matrix), 1.5-dimensional square (where the probe elements arearranged as a square matrix, but with different lengths of probeelements), one-dimensional annular (where the probe elements arecircular and concentric), two-dimensional segmented annular (where theprobe elements are arranged in segments along concentric, annularpaths), and one-dimensional circular (where the probe elements areoriented radially).

Returning to FIG. 7, the coaxial cable 69 leads to a phased arraycontroller 63 containing phased array control circuits 68. The controlcircuits 68 are customized to have a limited number of pulse channels(typically only a fraction of the total element number in order toreduce cost) and a certain amount of switches to control which elementsamong them are triggered by the pulses each time. Explicitly, the phasedarray control circuits 68 select a group of probe elements 65 and usethe selected group to generate ultrasound by sending a high voltagepulse to each of the probe elements 65 in the selected group. The probeelements 65 in the selected group thus contribute to the activeaperture, i.e., active probe length. The probe elements 65 convertelectrical energy to mechanical energy in the form of ultrasonic waves,which are transmitted to the tubular under test. The high voltage pulsescan be sent at the same time or at different times, i.e., with differenttime delays. If the latter, the ultrasonic beam could be steered to adirection other than the normal direction of the probe. After ultrasoundgeneration, the phased array control circuits 68 can select the samegroup or a different group of probe elements to receive ultrasonic wavescoming back from the tubular under test. The probe elements 65 receivingthe ultrasonic waves would convert the ultrasonic waves into electricsignals, which would then be received by the phased array controlcircuits 68 and processed. The electrical signals can be delayeddifferently and then summed in the phased array controller 63, as shownat 61. Time delay processing in both the ultrasound generation andreceiving is referred to as electronic steering.

FIG. 9 shows the tubular 12 with a radial plane 82 and an axial plane84. The axial plane 84 is along the axial axis 15 of the tubular 12,while the radial plane 82 is perpendicular to the axial plane 84.Initially, the ultrasonic probe (62 in FIG. 2) is oriented such that theazimuth plane of the ultrasonic probe 62 coincides with the axial plane84 of the tubular 12 and the elevation plane (perpendicular to theazimuth plane) of the ultrasonic probe 62 coincides with the radialplane 82 of the tubular 12. To detect flaws in all orientations, theprobe system must have the ability to generate ultrasonic beams that areeither in both the radial plane 82 and axial plane 84, or at an anglewith one or both of the radial plane 82 and axial plane 84. This isdemonstrated with reference to FIGS. 9-11.

Referring to FIG. 9, to detect a longitudinally-oriented flaw, i.e., aflaw parallel to the axial axis 15 of the tubular 12, ultrasonic beamsgenerated by the ultrasonic probe have to reside in the radial plane 82of the tubular 12 that contains the incident point “P”, but at an angle,typically between 13° and 20°, with the axial plane 84 of the tubular 12that contains the point “P”. The ultrasonic beam direction for detectinga longitudinally-oriented flaw is indicated at 73. FIG. 10 shows across-section of the tubular 12, along the radial plane 82, withultrasonic beams 75 in the tubular 12 for detectinglongitudinally-oriented flaws.

Returning to FIG. 9, to detect a transversely-oriented flaw, i.e., aflaw that is perpendicular to the axial axis 15 of the tubular 12,ultrasonic beams generated by the ultrasonic probe have to reside in theaxial plane 84 of the tubular 12 that contains the incident point “P”,but at an angle, typically between 13° and 20°, with the radial plane 82of the tubular 12 that contains the point “P”. The ultrasonic beamdirection for detecting a transversely-oriented flaw is indicated at 77.FIG. 11 shows a cross-section of the tubular 12, along the axial plane84, with ultrasonic beams 75 in the tubular 12 for detectingtransversely-oriented flaws.

Returning to FIG. 9, to detect an obliquely-oriented flaw, i.e., a flawthat is neither parallel to nor perpendicular to the axial axis of thetubular article, ultrasonic beams generated by the probe 62 are neitherin the axial plane 84 nor in the radial plane 82 of the tubular 12 thatcontains the incident point “P”, but at an angle, typically between 0°and 20°, with both the axial plane 84 and the radial plane 82. Anultrasonic beam direction for detecting an obliquely-oriented flaw isindicated at 79.

FIG. 12 shows a block diagram of a probe system 80 including the probeapparatus 10 described above and tubular 12. The probe support 32 andultrasonic probe 62 of the probe apparatus 10 are shown. The line 82between the probe apparatus 10 and the tubular 12 indicates that theprobe apparatus 10 is placed on the tubular 12, as shown in FIG. 2, orotherwise arranged such that the ultrasonic probe 62 can transmitultrasonic waves to and receive ultrasonic waves from the tubular 12.The probe system 80 includes a phased array controller 63, which isconnected to the ultrasonic probe 62. The phased array controller 63selectively applies varying time delays to the probe elements in theultrasonic probe 62 so that ultrasonic beams generated by the ultrasonicprobe can be steered into a direction in or off the normal direction ofthe probe. The probe system 80 includes a system controller 85, whichcan communicate with the phased array controller 63, as indicated at 86.The probe system 80 may include an actuator 54, as previously explained,for rotating a wheel of the probe support (or for rotating the probesupport 32) and locking the wheel (or locking the probe support 32) inplace. In this case, the system controller 85 may communicate with theactuator 54, as indicated at 88. Line 90 represents a rotatable linkbetween the actuator 54 and the probe support 32 of the probe apparatus10.

The system controller 85 includes a processor 92 and may include othersupporting devices, generally indicated at 94, such as a memory deviceand a display device. In one example, the processor 92 computes adesired tilt angle for the ultrasonic probe 62 to detect a particularflaw in a particular orientation in the tubular 12. The systemcontroller 85 may display the tilt angle information on a display deviceso that a user can read the information and then use the information torotate the probe support 32 to position the ultrasonic probe 62 at thedesired tilt angle. Alternately, the system controller 85 may send acommand signal to the actuator 54 to rotate the probe support 32 toposition the ultrasonic probe 62 at the desired tilt angle. Theprocessor 92 may also compute information that can be used toautomatically and electronically steer the probe elements of theultrasonic probe 62. In this case, the system controller 85 and thephased array controller 63 would work together to achieve the desiredelectronic steering of the ultrasonic beams.

The probe system 80 described above is equipped to generate ultrasonicbeams and receive ultrasonic beams in varying directions and angles. Thereceived ultrasonic beams are processed and interpreted to determine ifflaws are present in the tubular. The processing and interpreting may beachieved using the processor 92 or by manual calculations. By monitoringthe signals returning from the tubular wall one usually chooses a fewtime intervals where only low noise would appear for a flawless tubular.If the actually received signals within these intervals are larger thana specified level, they are interpreted to be caused by flaws. Asdescribed above, the probe support 32 can be rotated to tilt thescanning face (66 in FIGS. 2 and 3) of the ultrasonic probe 62 so thatthe ultrasonic beams it emits are at an angle with the axial plane ofthe tubular 12.

Furthermore, in the azimuth plane of the probe, ultrasonic beams can beelectronically steered into a direction other than the normal directionof the probe by applying varying time delays to individual probeelements within an active aperture of the phased array so that beams canalso be at an angle with the radial plane. These two angles (the oneachievable by rotation of the probe support and the one achievable byelectronic steering) can be adjusted independently, e.g., between 0° and20°. To detect flaws in any given orientation, as described above, thetwo required angles are calculated, either manually or using theprocessor. The probe support is then rotated to obtain the required beamangle with the axial plane, and proper time delays are applied to theprobe elements to obtain the required beam angle with the radial plane.For example, simple linear time delays (i.e., a constant time intervalbetween two adjacent delays) can be used to electronically tilt the beamat the proper angle relative to the radial plane.

One preferred design of an ultrasonic scanning probe apparatus of thepresent invention, as illustrated in FIGS. 13-17, is a phased arrayultrasonic probe apparatus 100 comprising a cavity 110 filled with wateror other suitable ultrasonic wave propagation fluid (not shown), andsealed with an acoustically transparent membrane 120 (FIG. 17). Themembrane 120 is intended to contact the outside surface the pipe 130 orother surface being scanned for flaws, and replaces the flowing liquid(typically water, but may be other liquids) as the acoustic couplant.The membrane itself is made of a material that is sonically‘transparent’ to the ultrasonic frequencies used by the probe. Thisarrangement therefore allows essentially ‘dry’ acoustical testing of thepipe 130 (as long as the pipe surface is dampened by an acousticcoupling fluid), as the acoustic couplant is sealed within the cavity110 of the probe apparatus 100 by the acoustically transparent membrane120. This arrangement, therefore, eliminates the need to continuouslysupply acoustic coupling fluid between the ultrasonic probe and theoutside surface of the pipe. In addition to being much easier, and farmore convenient to use, this arrangement also allows for ultrasonictesting for flaws in tubulars in areas where it would not be practicalto handle the supply and drainage of the large quantities of runningacoustic coupling fluid presently applied to pipes as an ultrasoniccouplant. This may be especially useful in very cold climates wherefreezing the water (or other fluid) may be a problem, or in crowdedareas where slipping hazards may exist, or in areas where largequantities of clean couplant fluid are difficult to obtain. In addition,the sealed system eliminates measurement variables that may exist in the‘running fluid’ systems.

As illustrated in FIG. 17, a bottom view of the probe apparatus is showngenerally at 100, showing the membrane 120 in place. The cavity 110(shown in FIG. 13) between the face of the phased array probe 115 andthe membrane 120 may be filled with water or other type ultrasoundcouplant. In operation, while the beam angle position block 140 rides onthe pipe surface 135 (as shown in FIG. 16), the membrane 120 will be incontact with the pipe outside surface 135 so the ultrasound from thephased array probe 115 can be coupled into the pipe body 130 through thefluid in the cavity 110 and the membrane 120, therefore running acousticcoupling fluid is not needed for sound coupling, as is the presentpractice.

In order to assure good contact between the membrane 120 and the pipebody 130, the membrane 120 may be allowed to protrude slightly from thehousing and remain slightly underfilled, so as to remain very flexible.This allows the membrane 120 to deform and therefore conforms to thepipe outside surface when it is brought into contact with the surface.This means that care must be taken to maintain proper fluid pressureinside the cavity 110. Therefore, some control of the fluid volume andpressure inside the cavity 110 is typically necessary. In addition, thefluid pressure which may be maintained inside the cavity 110 may also beused to control the contact pressure between the membrane 120 and thepipe outside surface. This pressure control may be achieved byinstalling a fluid regulating device, for example, but not limited to, acheck valve, through which acoustic coupling fluid can be injected intoor released from the cavity 110. There is a small amount of standoffbuilt into the beam angle position block 140 to assure that the membrane120 does not get pinched by the pipe while being used.

Shown in FIG. 14 is the scanner 150 with the beam angle position block140 partially detached from the housing 160. The beam angle positionblock 140 may be removable and modular so that many differentconfigurations of beam angles and pipe diameters are possible bychanging just the block 140. These beam angle position blocks 140 may besecured to the housing 160 by magnetic force (or other means) for easyand quick change of beam angle position blocks 140 of differingconfigurations. The beam angle position blocks 140 may be used to definethe angle between the azimuth plane of the phased array probe 115 andthe axial plane of the pipe 130, and the two planes intersect at thebeam entry point on the pipe 130 outside surface (see FIG. 9 and itsdescriptions). This angle changes when the probe housing 160 is tiltedto a different position in the radial plane of the pipe by using adifferent beam angle position block 140, as a result, the contactbetween the membrane 120 and the pipe 130 also changes. Because themembrane 120 is very flexible, it can deform and re-conform to the pipeoutside surface. This means the same scanner 150 can be used to detecttransversely oriented, longitudinally oriented, and obliquely orienteddefects—and to measure wall thickness by simply changing beam angleposition block 140. This is a notable improvement over conventionalultrasonic contact testing methods in the existing art where the phasedarray probe is coupled to a sound coupling block (a solid wedge) andthen the solid wedge is coupled to the part under test. In these priorsystems, the solid wedge defines the beam angle of the phased arrayprobe and different wedges are required for defects with differentorientations. The phased array probe is mounted to the wedge by screws.The ultrasonic probe of the present invention does not need these typesof wedges, which markedly improves its utility over the prior art, as itis a very time consuming task to change wedges.

As shown in FIG. 15, the scanner 150 is on a pipe 130 with a beam angleposition block 140 that orients the phased array probe such that theazimuth plane of the phased array probe coincides with the axial planeof the pipe and the elevation plane (perpendicular to the azimuth plane)of the phased array probe coincides with the radial plane of the pipe.This arrangement makes ultrasonic beams generated by the phased arrayprobe always reside in the axial plane of the pipe and may measure pipewall thickness if the ultrasonic beams are perpendicular to the pipeoutside surface and detect transversely oriented flaws in the pipe 130such as cracks and other flaws if the ultrasonic beams are in a anglewith the normal of the pipe outside surface.

In FIG. 16 is an embodiment where a scanner 150 may be provided with atilting beam angle position block 145 attached for detectinglongitudinally and obliquely oriented flaws on the pipe 130. In thisconfiguration the block 145 orients the phased array probe such that theazimuth plane of the phased array probe is at a non-zero angle with theaxial plane of the pipe and the elevation plane (perpendicular to theazimuth plane) of the phased array probe still coincides with the radialplane of the pipe. As explained in FIG. 9, in this arrangement,ultrasonic beams generated by the phased array probe can be used todetect longitudinally oriented flaws if they reside in the radial planeof the pipe that contains the beam incident point, but at an angle withthe axial plane of the pipe that contains the beam incident point. Inthis arrangement, ultrasonic beams generated by the phased array probecan also be used to detect obliquely oriented flaws if they are neitherin the axial plane nor in the radial plane of the pipe that contains thebeam incident point, but at an angle with both the axial plane and theradial plane.

With only a minor interruption in the work flow, one beam angle positionblock 140 may be exchanged for another. Therefore, due to the modularconstruction of the scanner 150, a collection of many different beamangle position blocks 140 may be readily interchanged for various typesof testing.

Also, because this ultrasonic scanning probe system uses a ‘closed’coupling media it may furthermore be useful in circumstances where aflowing liquid system of the prior art would not be practical. Forexample, in incidences where the environment is very cold, a watercouplant may be inappropriate due to freezing of the water, wherein inthe present invention a small amount of antifreeze may be added to theultrasound couplant allowing it to work properly. In other instances, asupply of running water to use as a couplant may just not be available.In still other instances, the environment of the testing area may nothave the drainage facility to dispose of running water.

Therefore, whereas the present invention has been described inparticular relation to the drawings attached hereto, it should beunderstood that other and further modifications apart from those shownor suggested herein, may be made within the scope and spirit of thepresent invention. Those skilled in the art, having benefit of thisdisclosure, will appreciate that other embodiments can be devised whichdo not depart from the scope of the invention as disclosed herein.Accordingly, the scope of the invention should be limited only by theattached claims.

1. An ultrasonic testing apparatus for detecting flaws in a tubular,comprising: a handheld scanner with a single ultrasonic probe mountedtherein comprising, a probe housing having a cavity adapted to contain aliquid acoustic couplant medium having an acoustic impedance, and thephased array probe mounted in a back wall of the cavity in the housing;a flexible and conformable acoustic coupler membrane mounted to theprobe housing and adapted to contact the tubular and having an acousticimpedance substantially similar to the acoustic impedance of the liquidacoustic couplant medium, the acoustic coupler membrane sealing theacoustic couplant within the cavity, to allow an ultrasonic couplingbetween the ultrasonic probe and a surface of the tubular, wherein, themembrane protrudes from the probe housing to acoustically couple withthe tubular and transmit the ultrasound between the phased array probeand the tubular; a fluid regulating device installed to the probehousing allowing the liquid acoustic couplant medium to be injected intoand released from the cavity of the probe housing to control the fluidpressure in the cavity; and a beam angle position block conforming tothe outside surface of the tubular, and orienting the phased array probewith the tubular.
 2. The ultrasonic testing apparatus of claim 1 whereinthe beam angle position block provides a replacable wear surface for theultrasonic probe.
 3. The ultrasonic testing apparatus of claim 1,wherein the bottom face of the beam angle position block is curved forplacement on the tubular.
 4. The ultrasonic testing apparatus of claim1, wherein the ultrasonic probe is a phased array probe.
 5. Theultrasonic testing apparatus of claim 1 wherein the cavity between thephased array probe and the membrane is filled with liquid acousticcouplant.
 6. The ultrasonic testing apparatus of claim 1, wherein thebeam angle position block may be detached from the housing.
 7. Theultrasonic testing apparatus of claim 1 wherein the beam angle positionblock is secured to the probe by magnetic force for rapid changing ofbeam angle position block with different tilting angles.
 8. Theultrasonic testing apparatus of claim 1 comprising a non-tilting beamangle position block attached for detecting wall reduction andtransversely oriented flaws in the tubular.
 9. The ultrasonic testingapparatus of claim 1 comprising a tilting beam angle position block fordetecting longitudinally and obliquely oriented flaws in the tubular.10. An ultrasonic testing apparatus for detecting flaws in a tubular,comprising: a probe housing having an axial axis, a central cavity lyingalong the axial axis, and a bottom face adapted for placement on thetubular, the bottom face having an opening in the middle; a probesupport disposed within the central cavity and rotatable about the axialaxis of the probe housing; and an ultrasonic probe mounted on the probesupport and having a scanning face exposed to the opening of the bottomface of the probe housing, the scanning face being oriented relative toa selected plane of the tubular by rotation of the probe support aboutthe axial axis of the probe housing.
 11. An ultrasonic probe system fordetecting flaws in a tubular, comprising: a probe housing having anaxial axis, a central cavity lying along the axial axis, and a bottomface adapted for placement on the tubular, the bottom face having anopening in the middle; a probe support disposed within the centralcavity of the probe housing and rotatable about the axial axis of theprobe housing; an ultrasonic probe mounted on the probe support andhaving a scanning face exposed to the opening of the bottom face of theprobe housing, the scanning face being oriented circumferentiallyrelative to a selected plane of the tubular by rotation of the probesupport about the axial axis of the probe housing, and the ultrasonicprobe having probe elements configured to generate and receiveultrasonic beams; and a phased array controller for selectively applyingvarying time delays to probe elements in the ultrasonic probe such thatthe ultrasonic beams generated by the ultrasonic probe are steered intoa direction in or off the normal direction of the ultrasonic probe. 12.The system of claim 11, wherein the bottom face of the probe housing iscurved for placement on the tubular.
 13. A method of testing a tubularfor flaws, comprising mounting a probe housing, comprising a beam angleposition block conforming to a diameter of the tubular, and orientingthe phased array probe with the tubular; the probe housing having acavity adapted to contain a liquid acoustic couplant medium having anacoustic impedance, and, the phased array probe mounted in a back wallof the cavity in the housing, providing a flexible, conformable acousticcoupler diaphragm adapted to contact the tubular having an acousticimpedance substantially the same as an acoustic impedance of thecouplant, sealing the acoustic couplant within the cavity with theacoustic coupler diaphragm, to allow an ultrasonic coupling between theprobe and a surface of the tubular, the membrane protrudes from theprobe housing to couple with the tubular and conduct the ultrasoundbetween the phased array probe and the tubular, placing the probe on thetubular with a scanning face of the ultrasonic probe exposed to detectflaws in the tubular through ultrasonic coupling of the acoustic couplerdiaphragm.
 14. The method of testing a tubular for flaws of claim 13wherein the ultrasonic probe is a phased array probe.
 15. The method oftesting a tubular for flaws of claim 13 wherein the cavity between thephased array probe and the membrane is filled with liquid acousticcouplant.
 16. The method of testing a tubular for flaws of claim 13,wherein the beam angle position block may be detached from the housing.17. The method of testing a tubular for flaws of claim 13 wherein thebeam angle position block is secured to the probe by magnetic force forrapid changing of beam angle position block with different tiltingangles.
 18. The method of testing a tubular for flaws of claim 17further comprising a non-tilting beam angle position block attached fordetecting wall reduction and transversely oriented flaws in the tubular.19. The method of testing a tubular for flaws of claim 17 furthercomprising a tilting beam angle position block for detectinglongitudinally and obliquely oriented flaws in the tubular.